Electrical insulator.



K. C. RANDALL, S. W. PARNSWORTH & 0. LE G. FORTESGUE. ELECTRICAL INSULATOR. APPLICATION FILED DEG 31,1913. RENEWED JAN.14, 1915,

1,129,521. Patented Feb. 23, 1915.

' INVENTORS- l l N ITED STATES PATENT KARL C. RANDALL, OF EDGEWOOD PARK, AND SIDNEY W. FARNSNORTH AND CHARLES LE G. FORTESCUE, OF PITTSBURGH, PENNSYLVANIA, ASSIGNORS T0 'W'ESTING- HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENN- SYLVANIA.

Specification of Letters Patent.

Patentedlheb. 23, 1915.,

Griginal application filed April 30, 1910, Serial No. 558,744. Divided and this application filed December 31, 1913, Serial No. 809,?46. Renewed January 14, 1915. Serial No. 2,277.

. Serial No. 558,744.

()ur invention relates to electrical insulating bodies or structures and particularly to such as are employed for supporting highvoltage lines or conductors.

' The object of our invention is to provide an insulating support for electrical conductors that shall be simple in structure and that, for a given voltage, may be of minimum practical dimensions, and of maximum economy of construction, or that, for a given size, may be capable of withstanding higher voltages than insulators of other forms or constructions.

In another application, Serial No. 558,744, filed April 30, 1910, we have disclosed the general principles of our invention and have broadly claimed insulating structures to which said principles have been applied. The present application discloses and covers certain specific stnuctures disclosed in the original application.

Our invention is illustrated in the accompanying drawing, Figure 1 of which is a view in section andin side elevation of a supporting structure'for a high-voltage conductor that is constructed in accordance therewith, and Figs. 2 and 3 are similar views of modified forms of the device shown in Fig. 1. One-half of the insulating body is shown in each of the figures in cross-section, and the electric field existing in the insulating body-is represented in the other half by broken lines.

in the device of Fig. 1, a conducting plate 1, or other suitable supporting structure, is provided'with-an aperture through which a rod 2 projects, the upper end of the rod being enlarged, and being preferably in the form of a sphere. The lower end of the rod 2 is provided with a clamp 3 whereby a conductor or line wire 4 is secured to and supported by the said rod. The upper end of the rod is surrounded by a cap or shield 5, the main portion of which is preferably substantially spherical and the inner face of which is substantially parallel to the enlarged upper end of the rod 2. The cap or .shield 5 is preferably secured to the support ing plate 1. The space within the cap or shield 5, between it and therod 2, is filled with a suitable insulating compound or body 6 that is extended so as to surround a part of the rod 2 below the supporting plate 1, the exposed portions of the said body being shaped to substantially conform to the direction of the lines of force of the static field existing between the rod 2 and the surrounding conducting parts. The cap or shield 5 protects the insulating body from the weather and also mechanically guards it, and it is so shaped as to-infiuence the electric field in the insulatingbody. In the preferred form of the device, the shield is so shaped relatively to the enlarged end of the rod 2 as to cause the lines of force of the said field, or the greater portion thereof, to be straight, whereas the lines of force representing the field between the diverging portions bf the rod and the surrounding parts is curved, all substantially as represented in the righthand portion of Fig. 1.

Fig. 2 represents a pin type insulator in which the rod 8, having an enlarged upper end, constitutes the supporting pin and is carried by a cross arm 9, or any other suitable support. The upper end of the rod 8 is surrounded by a cap or shield 10, the upper portion of which is substantially parallel to the upper enlarged end of the rod 8, and the lower portion of which is substantially bell-shaped and diverges laterally from the rod 8. The lower edge of the cap shield 10 is provided with a rounded rim 11, which avoids concentration of stress upon this portion of the shield. The shield 10 is provided, upon its top, with an apertured lug or a suitable clamp 12 for engaging and supporting a conductor 13. A body of suitable insulating material 14 is interposed between the upper enlarged end of the rod 8 and the adjacent substantially parallel portion of the shield 10, the exposed portion of the insulating body being shaped to substantially conform to the direction of the lines of force constituting the static field existing between the rod 8 and the shield 10.

The device illustrated in Fig. 3 is a suspension type of insulator which comprises a shield 16 similar to the shield 10 of Fig. 2, but somewhat different in form. The substantially spherical top portion of the shield 16 is extended to surround a greater portion of the enlarged upper end of the rod 17 than in the device of Fig. 2, in order that, when the space between the said parts is filled with suitable insulating material,- the rod cannot be pulled out of the shield unless the force exerted is very great and 'in excess of the tension to which the said parts will normally be subjected while in service. The shield 18 is provided with a lug 18 whereby the device may be suspended from any suit- 'able support, and the rod 17 is provided, at,

its lowerend, with a clip or clamp 19 similar to that employed in the device of Fig. for securing a conductor 20 to the lower en of the rod.

We claim as our invention:

1. An insulating support comprising a rod of conducting material having one end enlarged into a sphere, a substantially bell shaped conducting member inclosing the enlarged end of the conducting rod, and an interposed insulating body for maintaining the relative positions of the two conducting members and having its exposed surfaces so shaped as to conform to. the electric field existing between the members.

2. An insulating structure comprising a conducting rod havinga'n enlarged end, a conducting member surrounding the rod and having a portion that is substantially parallel to the enlarged end of the rod and another portion that extends laterally from the rod, and a body of insulating material interposed between the rod and said member the exposed portions of which are shaped to substantially conform to the direction of the static lines of force extending'between the said conducting parts. 7

3. An insulating structure comprising a conducting rod having an enlarged end, a conducting member surroundin the rod and having a portion that is su stantially parallel to the enlarged end of the rod and another portion that extends. laterally from the rod and is provided with a rounded rim, and a body of insulating Qua-terial interposed between the rod and said member the exposed portions of which are shaped to sub stantially conform to the direction of the static lines of force extending between the said conducting parts.

4. An insulating structure comprising a conducting rod having an enlarged end, a conducting member surrounding the rod and having a portion that is substantially parallel to the enlarged end of the rod and another portion that extends laterally from the rod, and a body of insulating material interposed between the rod and said memher the exposed portions of which are shaped to substantially conform to the direction of the static lines of force extending between the said conducting parts, the said conduct ing member extending laterally. beyond the insulating body.

5. An insulating structurecomprising a conducting rod having an enlarged end, a conducting member surrounding the rod and having a portion that is substantially parallel to the enlarged end of the rod and another portion that extends laterally from the rod, the said member bein also provided with 9. lug, and a-body of insulating material interposed between the rod and said member the exposed portions of which are shaped to substantially conform to the direction of the static lines of force extend-- ing between the said conducting parts.

6. An insulating structure comprising a conducting rod having an enlarged sub stantially spherical end, a conducting member having a substantially spherical portion surrounding the enlarged end of the rod and another portion that extends laterally from the rod, the said member being also provided with a rounded rim, and a body of insulating material interposed between the rod and said member the exposed portions of which are shaped to substantially conform to the direction of the static lines of force extending between the said con ducting parts.

7. An insulating structure comprising a conducting rod having an enlarged substantially spherical end, a conducting member having a substantially spherical portion surrounding the enlarged end of the rod and another portion that extends laterally I from the rod, and a body of insulatin material interposed between the rod an said member the exposed portions of which are shaped to substantially conform to the di rection of the static lines of force extending between the said conducting parts.

8. An insulating structure comprising; a

.conducting member provided with a recess conducting member provided with a recess and a downwardly and outwardly extending petticoat, a supporting rod pro ecting into body for maintaining the relative posltions 1913. of the conducting member in the supporting rod and having its exposed surfaces so the said recess, and an interposed insulating subscribed our names this 23rd day of Dec., 10

KARL G. RANDALL.

. SIDNEY W. FARNSWORTH.

5 shaped as toconform to the dlrection of' v static lines which intercept said conducting CHARLES LE FORTESGUE' member, the conducting member extending Witnesses: laterally beyondthe insulatin body. B. B. HINEs,

In testimony whereof, we ave hereunto W. M. MCCONAHEY. 

